The present invention relates generally to telecommunications networks, and more particularly to point-to-multipoint transmission within telecommunications networks.
Data originating from a single source may be delivered by a network forwarding engine to a plurality of destinations in a telecommunications network. This operation is sometimes referred to as a"multicast" or"point-to-multipoint" transmission. The forwarding engine includes a plurality of I/O interfaces from which data is sent to such destinations. Due to cost constraints, the total number of I/O interfaces associated with any single network forwarding engine, at present, is usually less than 32.
In order to indicate which I/O interfaces will be utilized for point-to-multipoint transmission it is known to use a bitmask having a bit corresponding to each respective I/O interface. For example, a 32-bit bitmask would be employed to designate I/O interfaces for point-to-multipoint transmission in a network forwarding engine having up to 32 I/O interfaces. However, as associated costs decline, network forwarding engines having greater numbers of I/O interfaces will be desirable, and the bitmask required by this known technique will eventually become impracticably large. Hence, there is a need for a forwarding mechanism which scales efficiently as the number I/O interfaces in network forwarding engines increases.